As Congress heard testimony from Flint's mayor about the water crisis there, some House and Senate candidates sent out fundraising pitches to their email lists mentioning the Michigan city's troubles.

In an email to supporters in his competitive Maryland Senate primary race against Rep. Donna Edwards, Democratic Rep. Chris Van Hollen, linked to a webpage titled "Stand With Chris," with a donate button at the top. It asked potential donors to "Join Chris in demanding justice" for Flint.

The Van Hollen campaign pointed to an Edwards email in which she provided her supporters a link to contribute directly to Flint victims. Like Van Hollen, Edwards asked supporters to "join" her – and if they do, they, too, are taken to a fundraising page for her campaign.

Political fundraising pitches are not unusual, but the sensitivity with which the Flint water crisis has been mostly treated is. It arose earlier this week in Michigan, where Republicans accused Melissa Gilbert, the Democrat challenging Republican Rep. Mike Bishop, of "playing politics" with the Flint crisis.

Like Van Hollen, Gilbert sent out an email asking her supporters to "join" her in urging "Congress to set aside partisanship and step up to help Flint." The email linked directly to a campaign fundraising page.

Ronna Romney McDaniel, the chairman of the Michigan Republican Party, said in a statement , "No one should fund raise off of the suffering of Flint families."

In Pennsylvania, Democrat Joe Sestak, a former lawmaker who is running against John Fetterman and Katie McGinty for the Democratic nomination to challenge Republican Sen. Patrick J. Toomey in November, compared the problems in Flint to ones that he warned will come in his own state due to shale fracking.

"Please contribute to my campaign today to send a leader to the Senate who was trained for 31 years in the Navy on how to stand tall – and avoid crises before they occur," he wrote in an email to his supporters , featuring four "CONTRIBUTE" buttons. In Ohio and Pennsylvania , down-ballot candidates are using Flint to talk about water issues in their own communities.